stringutils.java

文件为java程序

package org.hsuper;

import java.security.*; 

import javax.crypto.Cipher; 

import javax.crypto.SecretKey; 

import javax.crypto.SecretKeyFactory; 

import javax.crypto.spec.DESKeySpec; 



/**
 * 
 * 字符串工具集合
 * 
 * @author Liudong
 * 
 */ 

public class StringUtils { 

private static final String PASSWORD_CRYPT_KEY = Double.toString(Math.random()*1000); 

private final static String DES = "DES"; 



public static String getPASSWORD_CRYPT_KEY() {
	return PASSWORD_CRYPT_KEY;
}

/**
 * 
 * 加密
 * 
 * @param src
 *            数据源
 * 
 * @param key
 *            密钥，长度必须是8的倍数
 * 
 * @return 返回加密后的数据
 * 
 * @throws Exception
 * 
 */ 

public static byte[] encrypt(byte[] src, byte[] key)throws Exception { 

        // DES算法要求有一个可信任的随机数源

        SecureRandom sr = new SecureRandom(); 

        // 从原始密匙数据创建DESKeySpec对象

        DESKeySpec dks = new DESKeySpec(key); 

        // 创建一个密匙工厂，然后用它把DESKeySpec转换成

        // 一个SecretKey对象

        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES); 

        SecretKey securekey = keyFactory.generateSecret(dks); 

        // Cipher对象实际完成加密操作

        Cipher cipher = Cipher.getInstance(DES); 

        // 用密匙初始化Cipher对象

        cipher.init(Cipher.ENCRYPT_MODE, securekey, sr); 

        // 现在，获取数据并加密

        // 正式执行加密操作

        return cipher.doFinal(src); 

     } 

     /**
		 * 
		 * 解密
		 * 
		 * @param src
		 *            数据源
		 * 
		 * @param key
		 *            密钥，长度必须是8的倍数
		 * 
		 * @return 返回解密后的原始数据
		 * 
		 * @throws Exception
		 * 
		 */ 

     public static byte[] decrypt(byte[] src, byte[] key)throws Exception { 

        // DES算法要求有一个可信任的随机数源

        SecureRandom sr = new SecureRandom(); 

        // 从原始密匙数据创建一个DESKeySpec对象

        DESKeySpec dks = new DESKeySpec(key); 

        // 创建一个密匙工厂，然后用它把DESKeySpec对象转换成

        // 一个SecretKey对象

        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES); 

        SecretKey securekey = keyFactory.generateSecret(dks); 

        // Cipher对象实际完成解密操作

        Cipher cipher = Cipher.getInstance(DES); 

        // 用密匙初始化Cipher对象

        cipher.init(Cipher.DECRYPT_MODE, securekey, sr); 

        // 现在，获取数据并解密

        // 正式执行解密操作

        return cipher.doFinal(src); 

     } 

  /**
	 * 
	 * 密码解密
	 * 
	 * @param data
	 * 
	 * @return
	 * 
	 * @throws Exception
	 * 
	 */ 

  public final static String decrypt(String data,String password){ 

     try { 

      return new String(decrypt(hex2byte(data.getBytes()),

         password.getBytes())); 

    }catch(Exception e) { 

    } 

    return null; 

  } 

  /**
	 * 
	 * 密码加密
	 * 
	 * @param data
	 * @param password
	 * 
	 * @return
	 * 
	 * @throws Exception
	 * 
	 */ 

  public final static String encrypt(String data,String password){ 

    try { 

      return byte2hex(encrypt(data.getBytes(),password.getBytes()));
    }catch(Exception e) { 

    } 

    return null; 

  } 

/**
 * 
 * 二行制转字符串
 * 
 * @param b
 * 
 * @return
 * 
 */ 

  public static String byte2hex(byte[] b) { 

        String hs = ""; 

        String stmp = ""; 

        for (int n = 0; n < b.length; n++) { 

            stmp = (java.lang.Integer.toHexString(b[n] & 0XFF)); 

            if (stmp.length() == 1) 

                hs = hs + "0" + stmp; 

            else 

                hs = hs + stmp; 

        } 

        return hs.toUpperCase(); 

   } 

  public static byte[] hex2byte(byte[] b) { 

    if((b.length%2)!=0) 

       throw new IllegalArgumentException("长度不是偶数"); 

        byte[] b2 = new byte[b.length/2]; 

        for (int n = 0; n < b.length; n+=2) { 

          String item = new String(b,n,2); 

          b2[n/2] = (byte)Integer.parseInt(item,16); 

        } 

    return b2; 
  }
  public static void main(String[] arg)
  {
	 System.out.print("password:"+PASSWORD_CRYPT_KEY+"\n");
	 String str= StringUtils.encrypt("99999.123457",PASSWORD_CRYPT_KEY);
	 System.out.print(str);
	 str=StringUtils.decrypt(str,PASSWORD_CRYPT_KEY);
	 System.out.print("\n");
	 System.out.print(str);
  }
}